Question

how do redox reactions occur? by the formation of new chemical bonds between reactants by the switching of products and reactants by the transfer of electrons between reactants by the sharing of protons between reactants

Explanation:

Redox (reduction-oxidation) reactions are defined by the transfer of electrons: one reactant is oxidized (loses electrons) while another is reduced (gains electrons). The other options do not describe the core mechanism of redox reactions.

Answer:

by the transfer of electrons between reactants